Covid vaccines are expected to be offered to children in the UK aged 16 and 17, in line with many other countries, after a minister confirmed government experts will update their advice “imminently”.

Michelle Donelan, the universities minister, said the government was expecting an announcement from the Joint Committee on Vaccination and Immunisation (JCVI) on widening access to the coronavirus vaccine to more teenagers.

Just two weeks after the body recommended against routine vaccination of children, two government sources confirmed that the JCVI was reconsidering its ruling. Jabs for over-12s are currently limited to those who are clinically vulnerable or live with someone at risk.

The update in the advice was first revealed by Nicola Sturgeon, the Scottish first minister, who said on Tuesday that she “hoped” 16- and 17-year-olds would get the go-ahead to receive it after all.

Asked why the government was now going ahead with vaccines for 16- and 17-year-olds, Donelan told Sky News: “What we’re doing is waiting for the JCVI announcement; at every stage throughout the pandemic we’ve adopted their advice on this. They are the experts of course when we’re determining the vaccine rollout and we’ll await their imminent announcement shortly.”

Ministers are believed to have been in favour of older children getting access to the Pfizer or Moderna vaccines, and had asked the JCVI to keep the situation under review.

One of the concerns that the scientists raised, linked to the Pfizer jab, was about inflammation around the heart, with the JCVI concluding that the benefits did not outweigh the risk to those who would be receiving the jabs.

The government is hoping the country is past the worst of the third wave, with daily new cases of Covid across the UK falling to 21,691 on Tuesday and hospital admissions dropping to 731. There were 138 deaths. However, concerns remain about the possibility of the rate of new cases rising again once schools reopen in September, at the same time as many employers are expecting more workers to return to the office.

New findings released from the React 1 study show fully vaccinated people were three times less likely than unvaccinated people to test positive for Covid – around a 50% to 60% reduced risk, including asymptomatic infection. The data from Imperial College London and Ipsos Mori also suggested double-vaccinated people are also less likely to pass on the virus to others.

The study’s estimates are somewhat lower than figures from Public Health England that have suggested 79% protection against symptomatic infection for Delta after two jabs.

While the React study estimates had a considerable amount of statistical uncertainty, Prof Paul Elliott, director of the React programme, and chair in epidemiology and public health medicine at Imperial College London, said the difference – even when comparing effectiveness against symptomatic Covid – could in part be down to the populations involved, noting PHE’s data is based on those who come forward for testing, rather than a random sample.

“[With a] random sample of people, they may have symptoms but they may not go and get a test,” he said.

Older teenagers are one of the groups with the highest levels of Covid infections, so offering vaccinations to children aged 16 and 17 could potentially have a significant impact in dampening transmission.

Prof Rowland Kao, a participant in the the Scientific Pandemic Influenza Group on Modelling (Spi-M) and an epidemiologist at the University of Edinburgh, said: “Per capita, older teenagers currently have the highest risk of Covid-19 infection, and vaccinating 16- and 17-year-olds should reduce this.

“Current evidence also suggests that, even when vaccinated individuals get infected, they both are at lower risk of severe disease and their viral load drops more quickly than for unvaccinated individuals, with the likely consequence that they are less likely to infect others, though this is difficult to prove directly.

“Thus it is likely that vaccinating older teens will not only protect them, but also help protect others and dampen down any further waves of infection that may occur.

“This of course must be counter-balanced by the evidence for occasional side-effects of the vaccines themselves, for which there is some evidence that they occur with higher frequency in younger adults and older teens.

“While this risk is low, it is important that the evidence on which any decision that is made on further vaccination of older teens is made clear.”